Treatments of vascular stenosis or lesions during endovascular procedures, such as atherectomy, balloon angioplasty with or without stent placement, or ablation therapy, are associated with increased risk of distal embolization. Tissue debris, calcium, atheromatous plaque, and/or thrombi generated during the procedure often become lodged downstream in a small vessel of vital organs, causing tissue ischemia or infarction. For example, transient ischemic attack (TIA) and cerebral infarction (stroke) are common complications of performing endovascular procedures on the ascending aorta and the carotid artery.
To reduce the risk of distal embolism, several devices are employed for use in endovascular procedures. For example, blood filters can be deployed distal to a vascular lesion to capture emboli. However, disadvantages associated with the blood filters are that (1) dislodgment of embolic material can occur during insertion and retrieval of the filter device, and (2) blood filters cannot easily be used in small vessels, (e.g., a saphenous vein graft measuring 3 or 4 mm).
Another catheter system described in U.S. Pat. No. 5,833,650 includes occlusion members for providing proximal and distal occlusion to a vascular lesion. Each occlusion member communicates with an inflation lumen. The catheter includes irrigation and aspiration lumens for removing embolic debris generated during the procedure. The catheter also includes a device introducing lumen, which further increases the overall size and diameter of the catheter, making the catheter impracticable for use in smaller vessels.
Theron developed a device having an insertion catheter, a dilation catheter, and an occlusion catheter assembled in a coaxial arrangement, U.S. Pat. No. 5,423,742. The catheter device is inserted across a vascular lesion which is dilated by the dilation catheter. Emboli generated during the dilation is removed by suction through the insertion catheter, while the occlusion catheter provides vascular occlusion distal to the vascular lesion. The major disadvantage associated with the device is that some of the embolic material will not be removed by irrigation and suction, thereby leaving the patient at risk for embolic complication.
Thus, there is a need for devices and methods which effectively remove embolic material generated during endovascular procedures, and that can be used in vessels having various diameters.